The serotonin has been known to play important roles in pathology of the mood disorders. We summerize the evidences of serotonin in pathology of the mood disroders in a view of neuroanatomical and neurochemical aspects. Nowaday, the selective serotonin reuptake inhibitors(SSRIs) may be practically the first line of antidepressants with traditional tricyclic antidepressants(TCAs). Authors review the role of serotonin in the treatment of the mood disorders, in a view of the general considerations in selecting antidepressants, pharmacology, therapeutic indications, side effects, doses of medication, drug-discontinuation syndrome, drug-to-drug interactions, and special therapeutic situations.